Elastic fluid turbine arrangement



June 6, 1939. J. H. DORAN ELASTIC FLUID TURBINE ARRANGEMENT Filed April 1, 1938 Dof'an, by.

Inventor: John H His Attorne Patented June 6, 1939 UNITED STATES PATENT OFFICE John H. Doran, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application April 1, 1931;, Serial No. 199,467

2Claims.

The present invention relates to elastic fluid turbine arrangements and is of particular signiflcance with regard to turbines operated at high temperatures of the order of 900 F. and

g having valve chests manufactured separately from the turbine casing. and secured thereto by welds. In arrangements of this kind difllculty is experienced when there is insufllcient flexibility between the valve casing and the turbine shell because the valve casing at times is very much hotter than the turbine casing.

The object of my invention is to provide an improved construction and arrangement of elastic fluid turbines whereby the aforementioned 1| drawback is overcome.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

The single figure of the drawing illustrates an elastic fluid turbine arrangement in accordance with my invention.

The turbine comprising a rotor having a shaft as III, a first stage Curtis type double row bucket wheel II and a plurality of low stage bucket wheels l2 secured to the shaft l0. Elastic fluid is conducted to the first row of buckets of the Curtis wheel II by a nozzle plate I! and fluid is con- 80 ducted to the low stage bucket wheels i2 by diaphragms it supported on an inner casing member I! which in turn is held on an outer casing it which may be made of ordinary or low creep strength steel. The shaft l9 passes through as an opening in the outer casing it. Leakage past said opening is reduced by the combination of a steam packing l1 and a suitable water packing I It. The outer end of the shaft is supported on :Ii'bearing II which in turn is held on the casing Elastic fluid is conducted to the first turbine stage, that is, to the nozzle plate II, by means of a valve chest 20. The chest has a casing which forms a valve chamber 2i and a channel 22 con- I necting the chamber 2! to the nozzle of the plate it. This valve chest is preferably made of high creep strength steel. A valve seat 23 is formed at the juncture of the chamber 2| and the channel 22. The flow of fluid from the chamber to.

90 the channel is controlled by a valve member 24 which has a stem 25 projecting through a guide 26. The guide 28 is in the form of a sleeve having a flange 21 suitably fastened to. a flange 28 annular weld 30.

formed at the upper end of the valve chamber 2!. In order to secure the valve chest to the turbine casing, I provide the chest, more particularly the portion which forms the valve chamber 2i, with a depending skirt or extension 29 sur- 5 rounding and spaced from the channel 22. The upper end of the skirt is sealed to the valve chest casing and the lower edge of the skirt 29 is secured to an opening in the turbine casing by an With this arrangement the skirt 29 and the channel 22 form a space 3| between them. During operation, the space 9|- is filled with elastic fluid leaking past the clearance formed between the adjacent surfaces of the nozzle plate I! and the first stage bucket wheel I I. The pressure of the elastic fluid in the chamber 3i will be somewhat lower than the pressure of the fluid inside the channel 22, but what is more important, the temperature of the fluid in chamber 3| will be much lower than the 0 temperature of the fluid inside the channel 22. This lower temperature will reduce the heat loss and the stresses set up in the weld III or, from another viewpoint, prevent excessive weakening of the welded structure due to high temperature. 25 Also, the long extensions on the valve casing permit the valve casing to expand easily without putting excessive stress on the welded joint.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Elastic fluid turbine including the combination of a casing having an opening, a valve chest having a casing forming a valve chamber and channel means connecting the chamber to the first turbine stage, and means securing the valve chest casing to said opening comprising a skirt entirely surrounding said channel means and united at one end with the valve chest casing and at the other end with the turbine casing.

2. Elastic fluid turbine including the combination of a casing having an opening, a valve chest having a casing with an extension forming a valve chamber and a channel, a first stage nozzle plate detachably supported on the extension at the end of the channel, and means uniting the valve chest casing and the opening comprising a skirt integrally formed with the valve chest casing and surrounding in spaced relation the extension and a weld securing the skirt to said opening, the welded portion of the skirt forming a smooth continuation of the turbine casing to reduce stresses in the weld.

JOHN H. DORAN. 

